Hydrogen is undoubtedly the viable energy source for future. Many storage materials have been proposed but only few if any come close to the US Department of Energy Requirements of the gravimetric and volumetric densities for storage and transportation. One of the high-priority goals of the Department of Energy is “Finding effective hydrogen storage materials” which they list as one of the most difficult challenges facing hydrogen-powered transportation.
It is considered that a hydride may be found which is light in density and high in hydrogen content and which may give up hydrogen at low temperatures and the metal so produced can be rehydrogenated and the cycle be continued for reasonable period of time. While we search such a dream material, it is clear that hydrides will remain critical industrial materials because of their many other applications (e.g. in nuclear applications). The finding described here makes it possible to produce the hydrides at a low cost and in an environmentally friendly way. Several hydrides of the alkali metals with B and Al may be synthesized this way. All these hydrides are currently the topic of intensive research and while all of them are more stable than needed for reversibility for automobile use, it is likely that there may be methods found to destabilize them. Therefore the use of the current method should be of great significance.
Whatever the future uses of this technique, there is one immediate possibility. The generation of hydrogen by the reaction of magnesium hydride with water for automobile use. The hydride can be used in a slurry (McClaine et al, [1]) or in hydride cartridges (U.S. Pat. No. 5,514,353). The method being patented here saves the cost of separately producing hydrogen and then synthesizing the hydride by metal-hydrogen reaction. The novelty of the method is that it eliminates the need of separately producing hydrogen from costly methods such as the splitting of methane at high-temperature and other fossil fuels. It also eliminates the need of CO2 sequestration which is a by-product of fossil fuel gasification. The chemical hydride slurry method, involving one of the metal hydride slurries may become viable in near future. The invention described here would influence the cost of the hydrogen fuel production in a very significant way as well as the cost of recycling Mg metal or magnesium hydride. It may make a difference whether the slurry method is economically viable or not. This document also refers to the synthesis of other hydrides directly from metal-water-hydroxide-HCl reactions. In each case however a metal oxide or a chloride forms which would require the cost of reduction to metal. We propose a reduction of the oxide and chloride by using sodium or sodium hydride which brings down the cost of recycling the reactants.
Below is listed some related U.S. patent documents. These are the patents that deal with generation of hydrogen using metal hydride water reaction. None of the methods duplicate the method described in the document above.
U.S. Pat. No. 5,958,098: Method and composition in which metal hydride particles are embedded in a silica network.
U.S. Pat. No. 5,308,553: Metal hydride compositions and methods.
U.S. Pat. Nos. 5,514,353 and 5,833,934: Demand responsive hydrogen generator based on hydride water reaction.
USPatent# 20040258613: Process for the production and purification of sodium hydride.
USPatent# 20050053547: Method for activating metal hydride material.
USPatent# 20020100682: Hydrogen recharging system for fuel cell hydride storage reservoir.
USPatent# 20030014917: Chemical hydride hydrogen generation system and an energy system incorporating the same.
USPatent# 20040166057: Powder metal hydride hydrogen generator.
USPatent# 20050058595: Reactor and method for generating hydrogen from a metal hydride.
U.S. Pat. No. 6,143,270: anhydrous magnesium chloride
U.S. Pat. No. 5,665,220: Electrolytic magnesium production
U.S. Pat. No. 6,372,017: Method for producing magnesium
U.S. Pat. No. 5,782,952: Method for producing magnesium
U.S. Pat. No. 4,720,375: Process for producing magnesium oxide
U.S. Pat. No. 5,162,108: Method for preparing active magnesium hydride